Uploading files to SharePoint Online via NextCloud

Hello,

I managed to setup NextCloud and form a connection with SharePoint Online, but there is a problem with uploading files from NC to SPO. When I try to upload a file it will say “Exception: File /sites/< site collection >/< document library >/test_file.txt does not exist.” Everything uploaded from SharePoint Online appears in NextCloud just fine though.

Error log:

In case someone ever lands on the same problem then the reason for such error is the site/subsite language. You must make it in English for it to work.

What log file is this? I am having Sharepoint issues and I am wondering if this particular log file will help me out.